Neutrinos are tiny elementary particles that played an important role in the early stages of the universe. Three types of neutrinos played an important role in the development of the so-called standard model of particle physics, also known as the "world formula". This model offers an explanation of the universe and describes the smallest components of matter and their interactions. However, earlier experiments showed unexpected measurement results that cannot be explained by the previous understanding of neutrinos.

To explain these anomalies, researchers suspect the existence of a previously undiscovered fourth type of neutrino – sterile neutrinos. However, new results from the so-called MicroBooNE experiment at the Fermi National Accelerator Laboratory (Fermilab) particle physics research center near Chicago (USA) now very probably rule out this possibility after several years of searching: The research group with the participation of researchers from the Laboratory for High Energy Physics (LHEP) and the Albert Einstein Center for Fundamental Physics (AEC) at the University of Bern has found no evidence of a fourth type of neutrino. The results were published today in the scientific journal Nature.